Final answer:
Mahatma Gandhi strongly advocated respect for others as essential for peace and harmony and developed ideas to eliminate conflict and promote peace in all relationships.
Step-by-step explanation:
The historical leader who strongly advocated respect for others as essential for peace and harmony and developed ideas to eliminate conflict and promote peace in all relationships is Mahatma Gandhi. Gandhi, also known as Mohandas Gandhi, led the nonviolent struggle for independence in India against British rule. He emphasized the principles of nonviolence, truth, and respect for all individuals. His philosophy of Ahimsa (nonviolence) inspired many and had a significant impact on movements for peace and human rights around the world.